1. Field of the Invention
The present invention relates to a method for correcting clutch data used for controlling a clutch, and more particularly to a method for correcting learned data for clutch control operation.
2. Description of the Prior Art
In the prior art there has been widely used a clutch control system for controlling the operation of a friction type clutch in which the clutch is coupled with an actuator and the amount of operation of the clutch is controlled by the actuator in accordance with an electric control signal generated by a control unit. The clutch control system of this type is employed in, for example, a vehicle automatic transmission system. In the case where the operation of the clutch is controlled by the use of the clutch control system of this type, precise clutch data corresponding to the relationship between the position of a member for operating the clutch and the amount of operation of the clutch is required to assure an appropriate clutch control operation. However, variation in this relationship occurs because of impressions in manufacture, and also with the passage of time due to the wear of the clutch disc and the like.
Accordingly, if precise control of the clutch is required, it is necessary to carry out appropriate correction of the clutch data representing the relationship by, for example, a learning operation. In the prior art, for correcting such clutch data, a meet position at which the clutch disc meets the associated clutch pressure plate is determined by a learning operation which is, for example, conducted each time the selector is set to its neutral (N) position, and the clutch data necessary for controlling the clutch is corrected by the use of the resulting learned data to obtain the corrected clutch data.
However, in the case where the learning operation for obtaining the learned data is carried out at the time a prescribed operation condition happens as described above, under certain operation conditions, it will be sometimes happen that the learning operation is not carried out for a long period of time, and this will cause a change in the feel of vehicle when it is driven because the engagement operation of the clutch cannot be smoothly carried out.